Intensity-modulated radiotherapy for hepatocellular carcinoma: dosimetric and clinical results.

Hee Chul Park,Won Il Jang,Sun Hyun Bae

doi:10.18632/oncotarget.19219

Abstract

Since the introduction of 3-dimensional conformal radiotherapy (3DCRT), new radiotherapy techniques have expanded the indication of radiotherapy for the treatment of hepatocellular carcinoma (HCC), from the hitherto palliative to a now curative-intent purpose. Intensity-modulated radiotherapy (IMRT), currently the most advanced radiotherapy technique, is considered an attractive option for the treatment of HCC, and is more widely applied because it can deliver a higher dose to the tumor than 3DCRT while sparing surrounding normal organs. However, the advantages and potential disadvantages of IMRT for treating HCC have not been fully established. This article deals with three different IMRT techniques, including static IMRT and volumetric modulated arc therapy using conventional multileaf collimator (MLC) mounted linear accelerators, and helical IMRT using binary MLC mounted helical tomotherapy machine. We review dosimetric and clinical studies for these IMRT techniques for the treatment of HCC.

Highlights

The role of radiotherapy (RT) for the treatment of hepatocellular carcinoma (HCC) has been limited because of the low tolerance of the whole liver to RT and the risk of radiation-induced liver disease (RILD) [1,2,3]
Compared with s-Intensity-modulated radiotherapy (IMRT) - Larger low dose region of the normal liver - Limitation of non-coplanar arc: availability of only asymmetric partial arc; Decrease of advantage duo to increased treatment time by couch rotation and increased MUs s-IMRT: static IMRT using step-and-shoot technique and sliding window technique delivered by conventional multileaf collimator (MLC)mounted linear accelerators, h-IMRT: helical IMRT using rotational dose delivery by binary MLC mounted helical tomotherapy, VMAT: volumetric modulated arc therapy using rotational dose delivery by conventional MLC mounted linear accelerators, 3DCRT: 3-dimensional conformal radiotherapy, OARs: organs at risk, MUs: monitor units
IMRT is divided into s-IMRT, VMAT, and h-IMRT according to beam delivery methods

Summary

INTRODUCTION

The role of radiotherapy (RT) for the treatment of hepatocellular carcinoma (HCC) has been limited because of the low tolerance of the whole liver to RT and the risk of radiation-induced liver disease (RILD) [1,2,3]. In larger HCC (> 8 cm), the mean dose was lower in 3DCRT than s-IMRT and VMAT, leading the authors to suggest that 3DCRT might be a more suitable technique for larger tumors (> 8 cm) located in the right lobe, in terms of minimizing the risk of RILD This size limitation of IMRT to achieve a maximal liver sparing effect was supported by another study that compared s-IMRT and proton beam therapy in 10 HCC patients [33]. Compared with s-IMRT - Larger low dose region of the normal liver (consider use of non-coplanar arc) - Limitation of non-coplanar arc: availability of only asymmetric partial arc; Decrease of advantage duo to increased treatment time by couch rotation and increased MUs s-IMRT: static IMRT using step-and-shoot technique and sliding window technique delivered by conventional multileaf collimator (MLC)mounted linear accelerators, h-IMRT: helical IMRT using rotational dose delivery by binary MLC mounted helical tomotherapy, VMAT: volumetric modulated arc therapy using rotational dose delivery by conventional MLC mounted linear accelerators, 3DCRT: 3-dimensional conformal radiotherapy, OARs: organs at risk, MUs: monitor units. Kim et al [56] reported that CP class www.impactjournals.com/oncotarget

45–60 Gy capecitabine

Findings

CONCLUSIONS